A passive device is referred to as a circuit device that is not capable of providing power gain. A capacitor, an inductor, and a resistor are all considered as passive devices. There are three types of commercially available inductors namely thin film type inductors, multilayered type inductors, and wire wound type inductors.
TW patent application publication No. 201440090 A discloses a multilayered type inductor (see FIG. 1) and a method of making the same.
The method of making the multilayered type inductor includes the steps of: laminating a first circuit plate 110, a second circuit plate 120, a third circuit plate 130 and a fourth circuit plate 140 (see FIG. 2A); attaching an assembly of a supporting film 150 and a bonding pad circuit 160 to the first circuit plate 110 (see FIG. 2B); transferring the bonding pad circuit 160 from the supporting film 150 to the first circuit plate 110 (see FIG. 2C); removing the supporting film 150 from the bonding pad circuit 160 (see FIG. 2D); sintering the first, second, third and fourth circuit plates 110, 120, 130, 140 and the bonding pad circuit 160 so as to form a multilayered substrate 100 (see FIG. 2E); and scribing the multilayered substrate 100 using a scriber 170 (see FIG. 2F), so that the multilayered substrate 100 can be broken into a plurality of multilayered type inductors 10 (see FIG. 1).
Referring to FIG. 1, each of the first, second, third and fourth circuit plates 110, 120, 130, 140 includes a respective one of non-magnetic bodies 111, 121, 131, 141 and a respective one of first, second, third and fourth circuit patterns 112, 122, 132, 142. Formation of the first, second, third and fourth circuit plates 110, 120, 130, 140 requires numerous steps (a total of at least 13 steps), including punching each non-magnetic body 111, 121, 131, 141 to form holes therein, filling conductive paste in the holes, forming the first, second, third and fourth circuit patterns 112, 122, 132, 142 and sintering before laminating the first, second, third and fourth circuit plates 110, 120, 130, 140.
The multilayered type inductor 10 thus formed has drawbacks, such as undesired non-ohmic contact and Joule-heating which may be induced at the interfaces between every two adjacent ones of the first, second, third and fourth circuit patterns 112, 122, 132, 142.
A conventional method of making a thin film type inductor includes steps of: forming a coil layer (a total of 10 steps); forming an intermediate layer on the coil layer; forming a top electrode on the intermediate layer (a total of 6 steps); forming a bottom electrode (a total of 6 steps); forming a protecting layer so as to form a layered structure with an array of thin film inductors; forming a plurality of stick-breaking lines and chip-breaking lines in the layered structure; breaking the layered structure along the stick-breaking lines so as to form inductor sticks; forming side face contacts on each of the inductor sticks; breaking each inductor stick along the chip-breaking lines so as to form the semi-formed inductor chips; and forming end face contacts on each of the semi-formed inductor chips. The end face contacts cooperate with the side face contacts to define terminal contacts of each thin film type inductor.
The aforesaid method of making the thin film type inductor is relatively complicated, such as requiring numerous steps to form the terminal contacts of each inductor chip.